The present invention relates to an electromagnetic regulating device, with a movable actuator, such as a piston, forming on the end an engagement region, and a coil device, which is stationary relative to the actuator and which is designed to exert a force on the actuator.
Such devices are generally known, e.g., in the form of regulating devices with permanent electromagnets, and are used for a wide range of purposes. The basic principle is that a piston is guided in a housing as an actuator, which has an engagement region on one end for the regulating task, and can typically be moved out of the housing by means of an electromagnet provided in the housing against the force of a restoring spring.
FIG. 3 illustrates such a known regulating device in a sectional side view. A piston element 10, guided in a housing 12 and pretensioned against the force of a restoring spring 14, has on one end an engagement region 16, which projects out of the housing 12, and on the other end a press-on, hollow, cylindrical anchor 18, which can be moved through a predetermined path along a cylindrical contact surface in a yoke element 20 of an electromagnet (formed by coil 22 in the coil housing 24), whereby the engagement region 16 (FIG. 3 shows the pulled back or pushed in operating state) extends out from the end of the housing on the engagement side.
As clearly indicated by FIG. 3, the structural realization of such a device is expensive and not uncritical, especially in terms of fit and tolerances. Therefore, during production and assembly, it is necessary to form tolerances of the appropriate bearing (e.g., bearing 26) as well as the contact surfaces in a controlled fashion. In addition, the mechanical installation, e.g., relative to the conical region 28 adapted to the magnetization characteristic curve, is not unproblematic. Because the device shown in FIG. 3 also requires continuous application of the signal to the electromagnets at all positions, i.e., pushing out of the engagement region 16 from the housing, this creates further problems in terms of control and electronics. Therefore, in particular, different switching and holding currents must be controlled and, in general, there is the problem of a permanent (and according to the particular application, also not inconsiderable) current consumption for an extended piston, because this must be held permanently against the force of the restoring spring 14 in the extended position. Therefore, especially for energy-critical applications, for which, e.g., only portable current supply means are available, there is also a need for improvement in this direction.